Generally, the processes of exploitation, exploration and/or intervention in an oil well involve the controlled descent or ascent of hanging intervention equipment, tools and/or tubular elements to and from the interior of the well. Said intervention equipment is hung inside the well and its position is controlled by an elevation and descent system which comprises a set of cables, a set of pulleys or rig (also known as traveling block) and a reel (also known as drawworks). Said elevation and descent system is designed to, under normal operation conditions, support the entire height of all the equipment and the string of pipes.
However, there exists the possibility of a failure event or accident occurring in one or more components of said elevation and descent system. This may be a human or a mechanical failure in some of the components of the elevation and descent system, such as a cable cut, failure of the reel breaking system, detachment or breakage of one of the components, etc. Upon an event such as this one, it is possible that the elevation and descent system will be incapable of supporting the weight of the hung elements, and that they will descend in free-fall toward the inside of the well, potentially damaging themselves and or damaging or obstructing the well. Furthermore, this type of failures can cause severe damage to equipment and personnel on the surface installation of the well, due to the violent movement of the affected components, the fall of equipment into the well and/or lashings caused by the rapid movement of cables from the elevation and descent system.
After such an accident has occurred, recovery operations are required, often with specialized equipment, to recover the equipment and pipes which may have fallen towards the bottom of the well, which are expensive and completely halt production or intervention work on said well. These types of operations are known in the art as fishing.
As a way of minimizing the damage and losses produced by these types of accidents and to further prevent the need to carry out fishing operations in wells, numerous security devices to be installed on a wellhead of an oil well have been proposed, meant to stop the fall of components into the well upon an eventual accident of this type.
One of such proposed devices is described in U.S. Pat. No. 3,467,224 A, of Contractors Services Inc., from 1969. Said patent describes an automatically activated pneumatic security device for securing a cable upon a cut of the cable of the travelling block outside the well. Said device is adapted only for securing cables and cannot be used to secure a string of pipes.
Another of such proposed devices is described in U.S. Pat. No. 4,372,706 A, of Exxon Production Research Co., from 1983. Said patent describes an automatically activated security device for securing a cable upon a cut of the cable of the travelling block outside the well. The described device, upon an accident, is automatically activated by means of the breakage of securing bolts. Said device is adapted only for securing cables and cannot be used to secure a string of pipes. Furthermore, since its activation requires the breakage of elements by the force of the cable and equipment during the fall, the device does not possess manual activation, and the securing bolts must be replaced after each activation.
It should be noted that all the above mentioned devices known in the art require, prior to their installation, the complete halt of all intervention activities and the total removal of all hanging elements in the well, either a string of pipes and/or cables for intervention equipment, which generates a substantial economic loss and loss of production and/or intervention time. Additionally, said devices, while designed to catch and secure a cable upon an accident, are not capable of carrying out additional functions, such as at least partially catching and securing a string of pipes. Another unfavorable aspect present in the devices known in the art is that the securing mechanisms commonly used are not equipped to catch and/or secure cables, pipes, intervention elements and/or combinations thereof which present irregular or non-circular cross-sections, since the securing elements, wedges or clamps are activated and moved simultaneously.